The present invention relates generally to mechanical tire presses and, more particularly, certain methods to enhance their mold height capabilities thereby extending the useful life of the mechanical tire presses.
In common tire presses generally of the "slide back" or "tilt back" types, a loader assembly is utilized to retrieve an uncured or green tire from a loading platform normally located adjacent or proximate to the press. The loader then places the tire on a tire mold or other suitable platform integral with the press and, subsequently, through mechanical operation of the press, a steam dome or other suitable fixture is lowered or placed onto the uncured tire. The enclosed chamber formed thereby is then subjected to heat sufficient to accomplish the vulcanization process.
While the existing mechanical presses may be adequate for the production of various narrow tread design tires, they will not accommodate the wider modern tire configurations. This, specifically, because the necessary height of the molds in which tires are cured has been forced to increase substantially beyond the capability of the existing presses. In the past, a majority of tire manufacturers produced a tire of narrow tread design. These tires were popular and, accordingly, mechanical presses were manufactured with mold height capabilities to coincide with the narrow configuration of these once popular tires. In the present tire market, the low aspect ratio tires of current popularity dictate an increased width of manufactured tires. These older presses are simply not capable of accommodating this enhanced mold height.
Because these mechanical presses are substantial in character and quite expensive, it is desirable to increase the mold height capabilities of the older presses. There have been attempts to accomplish the foregoing through several means. The most common is the simple vertical extension of the side link arm. This, however, poses substantial difficulties from an engineering and operational standpoint. In particular, as the press opens the side link mechanism is no longer in harmony and balance. At its distal operating point, the side link does not slowly decelerate as originally designed. With simple side link extension, the unit continues to accelerate through its normal termination point and, upon stopping, causes substantial and appreciable vibration and component stress. This then ultimately affects loading accuracy because the loading mechanism is normally mounted or affixed on a press beam attached to the side link mechanism. Another method to increase side link length is to change the geometry of the press side plates to maintain original acceleration and deceleration characteristics. Unfortunately, this method is extremely expensive and time consuming as it mandates removal of these large presses from their foundation. This is not only quite expensive, but it causes substantial, and appreciable, manufacturing downtime thereby further increasing the cost of this modification.
It is, accordingly, a principal object of the within to present methods of increasing the mold height capabilities of mechanical curing presses thereby extending their useful life.
It is a further object in the enhancement of mold height capabilities to provide a method whereby a press is not subjected to unusual or unnecessary jarring or vibrational characteristics as a result thereof.
Another important object of the within is to provide a method of mold height enhancement which is economically responsible and feasible and may be accomplished without press removal or substantial and appreciable manufacturing downtime.